ST. LOUIS – The Mets better win the NLCS in six games because – home-field edge or not – they would be at a distinct disadvantage for Game 7.

Rain came yesterday, and washed away a second game in this NLCS. The common theory was that the postponement was a favorable break for the Mets. Which it was. But only for Game 5, as now Tom Glavine starts tonight on full rest.

However, even if you want to concede Game 5 to the Mets – and, remember, Jeff Weaver pitched well against Glavine in the opener and he too now avoids pitching on three days rest – the Cardinals have the defending NL Cy Young winner Chris Carpenter vs. John Maine in Game 6. And, if there were to be a Game 7, St. Louis would use Jeff Suppan, who shut out the Mets over eight innings in Game 3, against, well, who knows?

“We have 11 pitchers and it is certain to be four or five [used],” pitching coach Rick Peterson said.

The most likely strategy would be to have Darren Oliver (no starts since Aug. 5, 2004) and Oliver Perez (on three days) tag-team as many outs early as possible, meaning a hybrid starter, strangely enough, known as Oliver/Perez.

Just about the only certainty is that it will not be Steve Trachsel, who is unlikely to ever pitch for the Mets again. If the Mets were to reach the World Series, expect Trachsel to be replaced on the roster by the healing Orlando Hernandez.

As reported in Monday’s Post, Mets officials were infuriated Trachsel essentially pulled himself from his start Saturday in Game 3 with no out, the bases loaded, the Mets already down 3-0 and the team desperate for starters to work deeper into games. Trachsel had been struck by a ball on his thigh. Nevertheless, the team had no intention of removing the righty even after he walked Albert Pujols on four pitches to load the bases.

However, Trachsel said his leg had stiffened up, pretty much forcing Willie Randolph’s hand, though no one was even warming up. Randolph refused to discuss the issue when asked on Sunday, but several club officials made it clear that Trachsel had lost any lingering trust there was in him.

Trachsel said, “I’ve never done that ever, ever,” when asked about pulling himself from a game. He had said the previous day that the decision to be removed was “mutual.” As explanation for why he would not remove himself, Trachsel said he “waited 13 years for the opportunity” to play in the postseason. But, at this point, Carlos Delgado has distinguished himself after a 13-year wait to get into the playoffs. Trachsel has not.

Trachsel’s final job with the Mets could be to do the mandatory press conference for the next day’s starting pitcher setting up Game 7. Either that or the Mets can send in a group photo. “All hands on deck,” said Glavine, who even said he would be available for an inning or two if there were a Game 7.

Oliver has a chance to start coming off of a bullpen-saving six shutout innings in relief of Trachsel in Game 3. But he threw 72 pitches and Glavine pointed out, “You don’t know how Darren will bounce back from that.” Glavine conceded that with Suppan fully rested, St. Louis would “be in a better situation than us.”

Peterson said if the Mets have a chance to win Games 5 or 6, and had to use Oliver or Perez, they would. That is why he said, “Before you vote, you have to see who is even running for office. By the time we get there [to Game 7], one might have already been elected [to pitch in a previous game].”

Having an emergency situation does not assure doom. Bartolo Colon lasted just one inning in the decisive Game 5 last year for the Angels against the Yankees, and rookie Ervin Santana came on for 5 1/3 winning innings of relief. However, you don’t want to play longshots now. So the Mets really need to win this NLCS in six games, and avoid having to start a mystery man in Game 7 who has left just one clue so far.